Thermostat



May 15, 1934.

J. A. SPENCER THERMOSTAT Filed Sept. 6, 1930 /f l f fw null-m la 2 lPatented May` 15, 1934 THERMOSTAT John A. Spencer, Newtonville, Mass.,assignor to General Plate Company, Attleboro, Mass., a corporation ofMassachusetts Application September 6, 1930, Serial No. 480,153

4 Claims. (Cl. 297-15) This invention relates to thermostats, and withregard to certain more speciilc features, to ady justable thermostats.

Among the several objects of the invention may 4 i be noted theprovision of a thermostat of the snap-acting type having a wide range ofaction, both under snap-acting and other conditions, adjustable overwide ranges by means of the improved construction herein set forth.Other objects will be in part obvious and in part pointed outhereinafter.

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements of parts which 1Iwill be exemplied in the structure hereinafter described, and the scopeof the application of which will be indicated in the following claims.

In the accompanying drawing, in which is illustrated one of variouspossible embodiments of the invention,

Fig. 1 is a side elevation of the device;v

Fig. 2 is a plan view; and,

Fig. 3 is a cross section taken on line 3-3 of Fig. 2, the dotted linesshowing an alternate position of a corrugated thermostatic disc.

Referring now more particularly to Fig. 1, there is illustrated atnumeral 1 a circular body having an internal groove for peripherallysupporting a preferably radially corrugated, composite, thermostaticdisc 3 of the type set forth and described more particularly in myPatent No. 1,895,590, dated January 31, 1933, for snap-acting device.Broadly this disc comprises a composite sheet which is slightly conicaland having an opening 5 at the center. It is thus truncated. Thematerial from which the disc is formed comprises composite metal,sometimes referred to as thermostatic metal. This composite metalcomprises a sheet made up of a plurality of component sheets, theseveral component sheets each having a different coeiilcient of thermalexpansion. In its simplest form, with two metals only, it is commonlyknown as bimetal, The conical or bulged disc is radially corrugated, thecorrugations 7 being deeper at said central opening than at theperiphery, as shown. The disc 3 functions to snap from the solid-lineposition shown in Fig. 3 to the dotted-line position at one temperatureand to snap backat another temperature. Contacts 9 and 27 are providedfor making and breaking a circuit 11, for example, but it is to beunderstood that other functions may be performed, such as opening andclosing a valve. The stationary member 27 of the contacts is mounted ina bushing 29 in the casing 1. One of the wires 11 is joined to thecasing at an extension 25 and the other to the contact 27.

One of the objects of the present invention is to provide an adjustment,whereby the temperature differential at which the disc operates may bechanged and also the temperature per se at which operation takes place.

The above is accomplished by suspending from the periphery of the ring1, at preferably 120 intervals a group of tension springs 13 which arefastened downwardly to a nut 15 into which nut 15 is threaded anadjusting rod 17. The rod 17 carries an adjusting knob or wheel 19 atits lower end and reacts at its other end on the disc 3 when the disc isin its dotted line position. A shoulder 21 provides the reaction and anextension 23 through the opening 5 carries the other contact 9. Theshoulder is spaced from the disc 3 in closed position of the switch sothat when the switch opens, the contact opens only when the disc 3 isabout to snap. A cover plate 18, secured to the housing l, holds the rod11 in centralized position on the disc 3, but does not aiect thelongitudinal movement of said rod 1'1.

It is clear that without tension in the springs 13, the disc 3 willfunction between certain temperature limits to make and break contact,this being done by the said snap action. y

To change the limits of operation it is necessary only to turn the knob19, thus causing an action at the shoulder 2l, the rod 17 threading intothe nut 15. This resiliently places a strain in the disc, therebysetting up stresses therein, the reaction being brought about at theperiphery of the disc by means of the spring 13. The disc with its newset of stresses will then react with a snap action over a new and/orshorter temperature differential.

The construction provides a. fine adjustment over a wide range.

It is apparent that some of the' advantages of the invention may be hadby using an uncorrugated, snap-acting disc with the other elementsenumerated, such a disc being shown in Patent 1,448,240, dated March 13,1923. From this it will be seen that other forms of thermostats may belikewise adjusted within the meaning of the disclosure.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As many changes could be made in carrying out the above constructionswithout departing from the scope of the invention, it is intended thatall matter contained in the above description or shown in theaccompanying drawing shall be interpreted as illustrative and not in alimiting sense.

I claim:

1. An adjustable thermostat comprising a snap-acting, radiallycorrugated, composite metal disc, a threaded rod engaging the said disccentrally, a nut on said rod, mounting means engaging the disc at itsouter periphery, and at least one spring reacting between the nut andsaid mounting means.

2. An adjustable thermostat comprising a snap-acting, radiallycorrugated, composite metal disc, a threaded rod engaging the said disccentrally, a nut on said rod, mounting means engaging the disc at itsouter periphery, plurality oi equally spaced springs reacting betweenthe nut and said mounting means, and means controllable to be opened andclosed by said disc, said lastnamed means moving in accord with theposition of the center oi said disc.

3. An adjustable thermostat comprising a snap-acting composite metaldisc, a threaded rod engaging the said disc centrally, a nut on saidrod, mounting means engaging the disc at its outer periphery, and atleast one spring reacting between the nut and said mounting means.

4. An adjustable thermostat comprising a snap-acting composite metaldisc, a threaded rod engaging the said disc centrally, a nut on saidrod, mounting means engaging the disc at its outer periphery, aplurality of equally spaced springs reacting between the nut and saidmounting means, and means controllable to be opened and closed by saiddisc. said last-named means moving in accord with the position of thecenter of said disc.

JOHN A. SPENCER.

